Open hearth furnace



Nov. 28, 41933. G, w FlNNEy 1,936,621

OPEN HEARTH FURNACE Filed Sept. 14, 1931 2 Sheets-Sheet l G. W. FINNEYOPEN HEARTH FURNACE Nov. 28, 1933.

Filed Sept. 14. 1931 2 Sheets-Sheet 2 62 0 e 71 722139 g z yz m PatentedNov. 28, 1933 UNITED STATES Learn PATENT orrice Application September14, 1931 Serial No. 562,697

- 10 Claims.

This invention relates to improvements in open hearth furnaces and itconsists of the matters hereinafter described and more particularlypointed out in the appended claims.

The invention is more particularly concerned with the regenerators ofthe furnace and the associated rlues connecting them with the stack andblower system. In the operation of the fur: nace the products ofcombustion from the hearth pass through the regenerators at one end ofthe furnace and the checker work absorbs heat therefrom. After asuitable period, the passage is reversed with the incoming cooler airand gas (when the furnace is a gas fired one) entering through thatregenerator just mentioned, when the products of combustion from thehearth pass out the regenerator at the other end of the furnace to heatthe checker work for the next reversing pass through the furnace. Inthis manner, the regenerators are maintained at a high temperature topreheat the air (and gas) before the same reaches the hearth forcombustion.

Each regenerator has two compartments. or chambers and one is abouttwice the cross sectional area of the other and includes checker work inproportion. When using liquid fuels, both compartments are employed inpreheating air and when gas is used as a fuel the smaller compartment isemployed for preheating gas and the larger one is used for preheatingair. 7

Tests disclose undesirable conditions exist in the regenerators in thata channelling of the in coming air takes place and dead or inert spacesdevelop wherein the temperature remains the same regardless of whetherthe hot gases are passing out of the same or the cooler air is enteringthe same. Again such tests disclose that the temperatures in onecompartment often differs and in fact, in some instances, thetemperatures in the large compartment of the regenerator at one end ofthe furnace is the higher and in some instances the temperature in thesmaller compartment of the regenerator at the other end of the furnaceis the higher.

It is apparent that such uneven temperatures resulted in a loss ofefficiency and in an increase of the amount of fuel (either liquid orgas) necessary to support combustion with a resulting increase in thecost in making steel.

Attempts have been made to correct these conditions, such as by changingthe brick Work inthe neck arches so that the openings thereof were inproportion to the size of the associated chamber. Again, it has beenattempted to control the amount of cooler air entering each chamber inproportion to its size. Baffies have been resorted to in the chambers ofthe regenerator to make them a three-pass chamber. tioned had some valueso far as air preheating was concerned but a greater variance intemperatures was disclosed in the same regenerator.

The primary object of the invention is to pro.- vide a simple andeflicient means whereby the above mentioned objections are readilyovercome and which means is disposed outside the furnace easy for accessin the required adjustments which are maintained for long periods oftime.

A further object of the invention is to provide an improved meansassociated with the bulkhead ends of the chambers of the regeneratorswhereby the outgoing products of combustion may be controlled, so thatthe same is more evenly distributed in the chambers of the regenerators,channelling and dead air pockets or spaces are eliminated'and volume anddirection is regulated, thereby reducing fuel consumption with animproved economy and efliciency in operation.

- The above mentioned objects of the invention, as Well as others,together with the many advantages thereof, will more fully appear as Iproceed with my specification.

In the drawings:-

Fig. 1 is a View partly in top plan elevation and partly in horizontalsectionof an open hearth furnace embodying my invention.

Fig. 2 is a view on an enlarged scale, partly in end elevation andpartly in section of the bulkhead end of one of the regenerators andillustrates the damper members associated therewith.

. Fig. 3 is a horizontal detail sectional View on a further enlargedscale as taken on the line 33 of Fig. 2. I

In general, my invention contemplates the provision of sets of damperspreferably associated with and outside the bulkhead ends of theregenerators, which dampers may be set to control the volume anddirection of the outgoing products of combustion in a manner causing aneven temperature throughout each chamber of each regenerator and asubstantially equal .temperature in both chambers of each regenerator.Thus by setting the dampers of each regenerator in accordance with theconditions of the outgoing products of combustion to provide a uniformheat curve therefor, it is possible to retain such a curve for both theoutgoing products of combustion in one instance and the incoming air inthe other instance.

Ref rring now in detail to that embodiment of the invention, illustratedin the accompanying drawings:1 indicates as a whole the body of an openhearth furnace formed to provide a hearth 2, and 3, and 4 indicaterespectively the associated regenerators extending laterally from eachend of the furnace, both the body and the regenerators being buck stayedand braced in accordance with the practice employed in furnaces of thiskind. For the sake of simplicity and clearness, such buck stays andbracing has been shown only in a general way in the drawings herein.

In the furnace body, at each end of the hearth are the uptakes 5 and 6respectively, one disposed upon each side of the median plane of thefurnace body. When gas is the fuel employed one of said uptakes is usedas the gas uptake and the other one is used as the air uptake. Whenliquid fuel is employed, the same is fed into the furnace by nozzles atthe opposite ends of the body in the manner well-known, and then bothuptakes are used for air alone.

Each regenerator comprises the upright side and intermediate walls, '7and 8 respectively, roof 9 and inner and outer bulkhead walls 10 and 11respectively. In each chamber is provided the usual checker Work 12 andbelow the same are provided the associated ducts. The respective uptakesat each end of the furnace body are connected to the inner bulkhead endof the regenerator chambers by necks 13 and 14 respectively and theouter bulkhead wall terminates at its bottom insubstantially the planeof the checker work so as to expose the associated end of said ducts.

The ducts are connected by branches 15 and 16 respectively with a mainheader flue 17 leading to a stack 18. The main header is alsooperatively connected with an air duct 19 and suitable valves areprovided in the various ducts to control the outgoing products ofcombustion in accordance with the usual furnace practice,

At a location adjacent the outer bulkhead end of each regenerator andpreferably outside the same, I provide a suitable damper mechanism bywhich the volume as well as the directional distribution of both theoutgoing products of combustion and the incoming air (and gas if thesame is used for fuel) are controlled and which mechanism may beadjusted to meet the desired conditions.

In connection with such mechanism, I provide extensions 20 on theupright outer bulkhead walls of the regenerators which project outwardlybeyond the plane of the same and these extensions terminate at the topin substantially the plane of the bottom of the checker work. In saidwall extension are formed upright grooves 21.

In the plane of said grooves and associated with each chamber is a setof dampers in the form of a plurality of vertically movable plates 22-and 23 respectively, the outer ones in each set, having a guidedengagement in the grooves of' the wall extensions and certain other onesof the same set having means along one edge to provide grooves 24 toreceive the margins of the adjacent plates.

The plates of each set of dampers as shown herein are of a greatervertical height than is the height of the ducts below the checker workand may be raised and lowered in any suitable manner. As shownhereineach plate has operativelyconnected to its top endthe bottom.

end of a rod 25 and the top end of said rod is threaded and extends upthrough a suitable supporting member 26 common to all of the damperplates of both sets. Said support may be provided by a horizontallydisposed channel beam engaged by outstanding brackets 27 on the bulkheadwall of the generator. The rods mentioned extend up through openings inthe supporting member and are each provided with a nut 28 engaged uponsaid supporting member. Thus when the nuts are turned in one directionthe damper plates are raised and when the nuts are turned in the otherdirection they are lowered.

By means of the structure described, the various damper plates may beadjusted to those positions giving the best operation for the intendedpurpose.

The damper plates may be dry plates wherein no water cooling is providedbecause being outside the furnace, they will not be affected by thetemperatures of the outgoing products of combustion. However, thesedamper plates may be Wet or water cooled ones, should it be so desired.

In the adjusting of the dampers, temperature readings are taken atvarious points throughout the regenerators and when such readingsindicate dead pockets or channelling, then the desired damper in eachset is manipulated by either raising or lowering the same.

This will cause the outgoing products of combustion to take a definitepath thus regulating the volume, direction and distribution thereof, sothat the temperature is substantially equalized throughout theregenerator. In making these adjustments, the best results are ob tainedin working on the outgoing products of combustion because when thatregenerator is employed as an intake the temperatures of the chambersthereof remain uniform although this temperature gradually becomesreduced.

With such a mechanism, with the temperature being even throughout thechambers, said temperatures may be lowered to that one providing themost efficient action and as such even temperatures requires less fuelit is apparent that a saving in fuel is obtained. With the elimina tionof the dead spaces and channelling before mentioned, the burning out ofthe checker Work in the associated areas is also eliminated.

While in describing the invention, I have referred in detail to theform, arrangement and construction of the parts thereof, the same is tobe considered as illustrative only, so that I do not wish to be limitedthereto except as may be specifically pointed out in the appendedclaims.

I claim as my invention:-

1. In combination with a furnace, means providing regenerators withchambers therein connected at one end to the furnace, flues connected tothe other end of the regenerators, and means arranged closely adjacentone end of said regenerator and operable for controlling the volume anddirectional distribution of gases throughout the said chambers in thepassage of said gases through the regenerators to and from the flues.

2. In combination with a furnace, means providing regenerators withchambers therein connected at one end to the furnace, flues connectedthe volume and directional distribution of gases G throughout saidchambers in the passages of said gases through the regenerators to andfrom the flues.

3. In combination with a furnace, means providing regenerators withchambers therein connected at one end to the furnace and having abulkhead wall at the other end, flues connected to said bulkhead walland means disposed between said wall and flues and supported from saidwall and movable in the plane thereof for controlling the volume anddirectional distribution of gases throughout said chambers in thepassage of the same through the regenerators to and from the flues.

4. In combination with a furnace, means providing regenerators withchambers therein connected at one end to the furnace and having a bulkhead at the other end, flues connected to said bulkhead and dampermembers supported from and movable in the plane of the bulkhead forcontrolling the volume and directional distribution of the gasesthroughout said chambers in the passage of the same through theregenerators to and from the flues.

5. In combination with a furnace, means providing regenerators withchambers therein connected at one end to the furnace and including abulkhead at the other end, flues connected to said bulkhead, and aplurality of damper members associated with each chamber and supportedfrom said bulkhead and movable in the plane of the same, said dampermembers being individually adjustable to control the volume anddirectional distribution of gases throughout said chamber in the passageof the same through the regenerators to and from the flues.

6. In combination with a furnace, means providing regenerators withchambers therein connected at one end to the furnace and including abulkhead at the other end, flues connected to the other end of the saidbulkhead, a plurality of individually adjustable damper membersassociated with each chamber and supported from said bulkhead andmovable in the plane of the same for controlling the volume anddirectional distribution of gases throughout said chambers in thepassage of the same through the regenerators to the flues and vice versaand means on said bulkhead and on said damper member respectively forguiding said members in their adjustments.

'7. In combination with an open hearth furnace, means providingregenerators with chambers therein connected at one end to the furnace,flues connected to the other end of said regenerators and means arrangedclosely adjacent and supported for movement in the plane of the lastmentioned end and operable to control the volume and directionaldistribution of said gases throughout said chambers so as to eliminatedead spaces and channeling action of said gases in their passagesthrough the regenerators to and from the flues.

8. In combination with an open hearth furnace, means providingregenerators with chambers therein connected to the other end of saidregenerators and means supported by but closely adjacent the lastmentioned end and movable in a plane parallel therewith for controllingthe volume and directional distribution of said gases throughout saidchambers so as to eliminate dead spaces and channeling action of saidgases in their passage through the regenerators to and from the flues.

9. The method of operating a furnace of the kind described whichincludes a regenerator chamber and a flue connected thereto at the bulkhead end thereof and which method consists in taking temperaturereadings in various parts of the regenerator chamber to locateunequalized temperature conditions therein and then changing the shapeand cross sectional area of the bulk head end of the chamber to modifythe volume and direction of the gases and thereby substantiallyequalizing the temperature throughout said chamber.

10. The method of operating a furnace of the kind described whichincludes a regenerator chamber and a flue connected thereto at the bulkhead end thereof and which method consists in taking temperaturereadings in various parts of the regenerator chamber to locateunequalized temperature conditions therein and then changing the shapeand cross sectional area of the outlet of said chamber to modify thevolume and di rection of the gases and reduce draft action in certainother portions of said chamber to modify the volume and direction of thegases to substantially equalize the temperature throughout said chamber.

GEORGE W. FINNEY.

